Means for securing hairsprings to arbors



- Sept 1943- B. J. FIX 2,329,710

MEANS FOR SECURING A HAIR SPRING TO AN ARBOR Fiied Jan. 23, 1939 h-LVETL L EIV E 521111 lFix Patented Sept. 21, 1943 I UNITED STATES, PATENT et MEANS FOR SECURING HAIRSPRIINGS 7 T ARBORS 7 Eugene J. Fix, Philadelphia, Pa., assignorto the United States of America, as represented by the Secretary of War- I Application January 2 3, 1939, Serial No. 252,418 7 Claims; (01. 58-115),

(Granted under the act of March 3, 1883, as a amended April 30, 1928; 370 0. G. 757) The invention described herein may be manunecessity of deforming 'any part of the' spring factured and used by or for the Government for or employing extraneous steps or meansto pregovernmental purposes, without the payment to serve the balance of the arbor. me of any royalty thereon. The'specific nature 01' the invention as well This invention relates to a method and means as other objects and, advantages thereof will for securing a straight length hair spring to the arly ppe r from a description of a preferre escapement arbor of a timing mechanism, and im nt s Shown in the accompanying more especially the timing mechanism of a-medrawing in which: I chemical t fuse r Fig. 1 is a sectional view of one of the pivot Owing to the sturdiness of construction and ,IO ofran escapement bo a higher frequency of vibration afiorded by hair 5 a t o al vi of the h Pivot springs of rectangular cross-section and straight Section of the'escapementnrbor;

length, hair springs of the helical or similar 3 is a top p Viewef t pivot Section t have b largely supplanted by t former of Fig. l with the hair spring in the position in t in th prior t which it will be secured by the'pivot section of In utilizing straight length hair springs the 2 t Q" commonplace method of securing the hair spring 4 is View in elevation Showing t Pivot to the escapement arbor has been to bore the sections of Figs- 1 d a e dt form an arbor to provide a passage of circular form eX- escapement arbor with t h attached.

tending therethrough normal to its axis, insert Referring now h drawing wherein the the straight length hair spring of rectangular Same elements. are identified y the e Chercmss seetion Within the passage to a position .acters of reference throughoutthe views, there where its opposed ends protrude from the-cor- Shown in Figvl n escapement arbor P ot responding opposed ends of the passage sub- Section I provided with the usual p e g stantially equal amounts, and secure the hair t. bearing t n 2 dapted to o ci at b vs up t spring in position by means of a circular wedge h DiVOt S t on When p p y t d inthe driven into the passage. To properly'secure' the cooperating bearing i n. an r s p r I hair spring to the arbor against relative dis not Shown- I placement by means of a circular wedge it is The escapement I Q Pivot Section may necessary to drive the Wedge within the passage 1-30 have any desired exterior contouri'but is P to a point where it deforms the portion of the ably to facilitate m in d hair spring within the passage into arcuate shape metrically arranged about an axis coinciding having a convex surface on a radius closely ap" forming a prolongation 'of the axis offbearing preximating the radius of the passage a portion 2 and of circular cross section throughsult oi the deformation of the medial portion out its axial extent- At its end 3 DDOS d to of the hair spring and the fact that the spring a P0111011 t arbor Divot Sect on I tertends to assume its normal rectangular crossktes in a plane no a tolits axis a d is sectional shape beyond the deformed portion, a y cylindrieelly bored Otherwise a ly compound bends or stresses are developed in the hollowed out iii any desired p p e Co fi u spring adjac nt t b upon vibration or, tion to form a recess 4 having a' flat end' defle'xure of the spring which rapidly fatigues the ing S r ce 5 Darallel-tothe plane of end 3. same and introduces an omnipresent factor of A slot 6 of substantially the same geometrical non-uniformity of action and/or failure. cross-section asthe hair spring 8 to be employed,

or prime importance among the desiderata e e shown of rectangular cross-section, and

of a mechanical time fuse is simplicity of conpreferably of such width as to frictionally enstruction and positive, precise functioning of opage and securely hold the hair'spring in place, crating parts; and therefore it is an object of is extended diametrically across. the arbor pivot this invention to simplify the method of attachsection l-and axially toward bearing portion! ing a straight length hair spring, normally of, beyond surface 5 a distance closely approximatrectangular cross-section, to an escapementjo ing t e eo sp dimensioned. t e hair r r, r spring. Accessto the slot 6' is providedffor by It is a further object of this invention to prodiametrically disposed openings 1 leading from vide simple means to effectively secure a straight the end 3 of the arbor pivot section to the slot 6.

length hair spring normally of rectangular cross- The escapement arbor pivot section 9 shown section, to an escapement arbor without the in Fig. 2 cooperates with the escapement arbor r arbor assembly. The pivot section 9 is provided with a projecting bearing portion]! adapted to be seated in a cooperating bearing portion of an arbor Support, not showrrand to act with bearing portion 2 to preserve alignment of the escapement arbor assembly in oscillation.

It will be observed, that although I have shown the slot 6 in pivot section 'I that this has been done merely for the purpose of illustration, in as much as it is functionally immaterial whether the slot 6 be located as shown in Fig. 1 or in the body portion of pivot section 9. If the slot 6 is located in body portion 9, then the openings 1 serve to prmitfthe insertion of the body portion T0 or pivot Section? and the hair spring 8 secured in the slot within recess '4 "of pivot section I. In bther instances dingy be desirable to. ons the slot partially in'pivot section '2 maternally in "the body [0 of pivot section 9 "so as to compel the assembly of the two pivet'seetions in a predetermined certain position relative to each otherbyemp'ieying the hair spring as a key extending betw'enthe'slotted portions 'of each pivdt section. This latter method may at times be desirable to facilitate balancing Of the arbor. l

In the use or 'tneeseap'ement arbor the uses escape'p'allets will 'be'suitablysecured to the assembled arbor shown in Fig. 4 for regulatingthe running of'the'es'capewheel of the timing mecha- 'nisin'of the fuse, and tne'opposed terininalpdrwheel; I

Having particularly 'de'scribed'what now "appears to in 'as'a preferredeinbodiinnt'ofthe invention I claim and desire to secure b'y'Letters Patent of the United States:

' '1. An escapement'arbor comprisin'g'two'pivot fSectibIlS, one Of Saidsectibi'isbon'iprising a bearmg ortion and being recessed inwardly from' its end opposed to 'said bearing portion, the Wall defining the recess b'eiiigcut away to provide oppositely disposed openings'extending axiallyinward'at "least "as 'far asthe recess, the other'o'f said pivot sectionshaving a body portion inserted into said recessan'd abearing portion inaxial alignment withsaidfirst na -med'bearing portion, said pivot 'section'sb'eing formed to provide "a passage 'of substantially uniform cross-section 'intercommunicating with'said openings.

"2.A 'devic'efor securing a transverse'meniber in position'comprising two sections, one of said sections being recessed inwardly from one end,

the 'wa'll deflning therecess being 'cutiaway-to provide oppositely "disposed "openings extending axially inward atleast-as far'asthe recess-the other' of said *sectionshaving a body port-ion inserted into said frecess,; said sections "being formed to "provide 'a' passage 'intercommu-nicating with said openings within which said transverse member may be secured to project through either of the openings.

3. A device for securing a transverse member in position comprising two sections, one of said sections being recessed inwardly from one end, the wall defining the recess being cut-away to provide oppositely disposed openings extending inward at least as far as the recess, the other of fsaid sections having a body portion inserted into 10 said recess, said sections being formed to provide a passage intercommunicating with said openings, and a transverse member within said passage. 7

4. In an escapement arbor comprising two pivot sections, one of said sections being recessed in-. wardly from one of its ends, the wall defining the recess having opposed removed portions to form openings extending axially inward substantially the same distance as the recess, said section being slotted inwardly beyond the recess from one opening 'to the o'ther to frictlonally engage a transversely positioned straight length hair spring of uniform cross section, said other pivot section including a body portion of a confignration similar to the recess fricti'onally' engaged in said recess.

5 An escapeinentaibor comprisedof two ipivot sections of which one section is substantially circular in cross-section throughout its axial length and is provided with a bearing portion projecting axially of the section, said one section,

being cylind'ric'ally airially bored "from its end op-po sitethebearing'portion to form a recess terminatingin a plane normal to the axis of the section and being diametrically slotted axially inward from said plane to receive a transverse hair's'pring of substantially uniform cross-section, opposite portions of the wall of said one section V defining the recess being removed to provide 40 openings extending to the slot to facilitate insertion of'the hair spri'ng within the slot,'the other pivot section o f'said arbor includinga bo dy section of substanti ally'the same configuration as "said rece's's'frictionally inserted therein andhavmg a projecting bearing portion in axial aligninent it"rith 'said'first named bearing-portion. An'scapemnt arborpivot'section comprising a section ofcircularcrdss section throughout the axial} eng th andabearing portion projecting axially ofthe section, said seetion being'cyiindrically axially bored from its end opposite the bearingportion-fto form a recess terminating in a .plane norrnalto the axis of the section and-being diametrically slotted inward from said plane to receivea transverse hair spring of uniformcr osssection, the wall of said section "forming the recess ,being removed to form opposed openings leading to'and communicating with the diametrical slot -to provide means whereby the hair spring may .be inserted in the slot. s w

7. In an escapement arbor, a recessed pivot section providedwith a bear-ingpertion, the wall defining the recess having opposed openings-extending axially-inward at least as far'as the cess, a secon'd pivot section having-a body portion "frictionallyengaged within the recess of thefirst -pivotsection, and a bearing-portion-on thesecond pivot section in axial alignment with the bearing 'Eportion: of the first section. I H l V O EUGENE JIFIX. 

